Spray drying process



Patented Dec. 22, 1942 SPRAY DRYING PROCESS James F. Walsh, Tuckahoe, N. Y., assig'nor to American Maize-Products Company, a corporation of Maine No Drawing. Application September 21, 1939,

Serial No. 295,908

3 Claims.

This invention relates to a spray drled composition and process of manufacture and more particularly to a substantially non-hygroscopic nutritious edible spray-dried powdery material adapted to be used in the baking, brewing and confectionery industries. The composition comprises essentially an intimate mixture ofsolidified starch conversion syrup and water soluble non-coagulable proteins derived from natural starchy substances and freed of impurities and with or without the addition of diastase; the product being prepared preferably in such a manner as to prevent material discoloration, or damage to the diastase.

Starch conversion syrups alone, such as corn syrup obtained by acid conversion of starch, have been spray dried before to produce a solid product but difiiculties have been encountered in producing the packaging the spray dried material because of its strong hygroscopic tendencies. Also, the product does not contain the proteins which are very desirable and essential in certain food products. In accordance with the present invention these difficulties and de ficiencies are overcome. has been found that if the starch conversion syrup is treated with a solution of soluble proteins to provide an intimate mixture (or when desired a heat reacted compound) and this resulting'substance is spray dried under controlled temperature conditions,-the proteins and syrup solids will coact or react to form a new spray dried product which is substantially non-hygroscopic and possesses the desired nutritious and other properties. The coaction or reaction of the constituents and accordingly the characteristic properties of the final product are controlled largely by the temperature conditions during spray drying.

The components of the composition of this invention are incorporated to form a substantially homogeneous mixture which is subsequently subjected to spray-drying or aeroform dryingwhere the temperature is controlled by a highrate of evaporation from large surface areas presented By this invention it to the drying medium. The finished product is soluble in water, substantially non-hygroscopic, and is free of discoloration when the drying is carried out at low temperatures. The product contains readily assimilable carbohydrates, nutrient salts, (e. g. phosphates, phytins, lactates) and proteins such as alburnens and amino acids; and is diastatically active when a diastase is used.

The starch conversion syrup component of the and certain salts,

composition may be obtained by acid or enzyme conversion of starch from any suitable source such as corn, wheat, rice, peas, beans, potatoes. The syrup in the usual case should contain a reducing sugars content (calculated as anhydrous dextrose) of about 25% to The syrup contains dextrose, maltose and dextrins in varying amounts depending upon the degree of conversion. Each of these constituents provide desirable properties in the final composition. The reducing sugars maltose and dextrose are utilized as fermentation agents for bakery and brewing products and as sugars in the confectionery products. The datrins, which are edible, supply assimilable carbohydrates. A common and advantageous form of starch conversion syrup is corn syrup or commercial glucose obtained by conversion of corn-starch with acid. heat and pressure in conventional manner, and containing about 40% to 42% reducing sugars- The water soluble proteins may be obtained from the above mentioned natural starchy substances such as corn, wheat, rice, etc or modified products thereof. The preferred source of these materials is com steep water that has been treated to move the undesirable substances particularly the heat coagulable solids and other non-assimilable substances. The steep water contains a substantial amount of soluble ingredients of the 'corn particularly soluble proteins such as phosphates and phytins, that have nutritive value and are desirable in food products. The steep water may be that obtained in the convention manufacture of corn starch by soaking or steeping the corn in sulphurous acid solution. In addition to the desirable soluble ingredients of the corn particularly soluble proteins, the steep water also contains some undesirable suhstancis such as the heat coagulable proteins and other non-assimilable substances.

A process for treating steep water to remove the undesirable solids and preserve the desirable proteins and other soluble materials is disclosed in the copending application of Stein, Walsh and Needle, Serial No. 131,366, filed March 1'], 1937. The process comprises principally neutralization of the steep water with an alkaline material, e. g. line, to a pH of about 6 to 7, which eifects coagulation of the imdesired solids, and filtering to remove the coagulated solids.

The filtered steep water contains about 5.9%

total solids; ash (mineral substances.il.88% and soluble protein content of 3.4% and has a Banm of about 5 to 6. It has a taste and flavor satlsfactory for use in the final composition; whereas the steepv water containing the original nonsoluble proteins and othersolids would be entirely unsuitable. If desired the steep water may be concentrated before or after neutralizae tion. The amount of proteins in the final product is controlled by the amount of filtered steep water used. These proteins are useful as a yeast food and provide a nutritious component in the composition.

The diastase material which may be used in this composition where a diastatically active product is desired, may be diastatic malt extract, diastase concentrates and other suitable enzymes.

A commercial form and source of this enzymatic material is takadiastase. The amount and type of enzyme added to the liquid composition will determine the diastatic content of the final spray dried product.

The composition of this invention may be prepared in several different ways and the characteristic features of the final spray dried composition will vary with the difierent procedures, as indicated by the following. The starch conversion syrup and solution of soluble proteins from natural starchy materials, for example refined steep water, may be intimately admixed and a very slight amount of heat employed just sufficient to condition the mixture for spray drying but insuflicient to cause any decomposition or discoloration of the ingredients or establishment of flavor due to heating. Such a'mixture would then be spray dried at relatively low temperatures suflicient to efiect dehydration and coaction between the proteins and syrup solids but insufficient to cause any of the above mentioned un-' desired changes. The resulting spray dried product is a substantially non-hygroscopic, colorless, free flowing powdery material. This product has a bland, cereal-like taste and because of this and its freedom from color it is particularly useful in white bakery and confectionery products, which prohibit any introduction of marked color or flavor. It is also adapted for use in ice cream where added color and marked flavor are not permitted.

To prepare a product having substantial dia- Y static activity but still substantially free of added flavoror color, the low temperature procedure outlined above would be followed and there would be incorporated in the-mixture prepared for spray drying a suitable amount'of orientillie; above 5 mentioned enzymes. The temperature of the 'compositionz during compounding and also dur- "spray drying "is maintained below the atwhich the diastase would be dam- 1 aged. this temperatur is .belowabout 150 F. Priortospray drying thespfif the composition is adjusted to the p iue tcsiveoptimum diastatic activityr This falls within the range'of about'4.5 pH to- 6.5 pH; The diastatically active and substantially colorless and tasteless product resulting from this procedure is particularly'useful in fermentation products wherein the diastase would facilitate fermentation and the proteins, carbohydrates and sugars would provide the nutritious elements.

In products where added flavor and color are not prohibited and particularly where they are desired, the composition of our invention will be heated sufiiciently to cause a definite color and flavor producing reaction to take place between the starch conversion syrup and the refined steep water or other water solubl proteins. This heat composition is spray dried: or the reaction may be caused to take place during the spray dryinl operation, or the spray-dried material may be heated in the dry form to eflect this reaction. 6 The dehydrating atmosphere, usually heated air, into which th composition is sprayed or atomized may be heated to a relatively high temperature that will raise the temperature or the sprayed material in suspension to about 150 I. 10 to 200 F. At such temperature the product will darken somewhat and develop a strong cereal flavor and odor and produce reaction products of the proteins, sugars and dextrins. This product may be used as a brewing or baking adjunct where its color and flavor would augment and improve the material color and flavor of the product to which it is added, while the sugar component of the spray dried product would assist in fermentation and the proteins and carbohydrates would advantageously increase the nutrient solids content of the product. If desired a dried diastase concentrate may be blended with this heat reacted spray dried material to make it diastatically active.

Where it is desired to augmentthe aroma and flavor of the above described heat-reacted prodnot it may be heated again after spray drying; that is, the solid dried material may be heated to produce the flavor and aroma. This will also apply to the low temperature coacted, spray dried product where it is desired to convert it into a product having marked flavor and aroma. The temperatures normally used for this purpose will be about 150 F. to 200 F., and preferably cooling the heated product rapidly to arrest reaction and facilitate any further necessary processing such as grinding and packaging.

The following illustrative but non-limiting example shows the preparation of one of the above described forms of my composition, which is substantially colorless and has a bland taste. Partially concentrated steep water containing about 10% to 15% solids including a substantial amount of undesirable insoluble salts and proteins, is neutralized with lime to a pH of about 6.4 to 6.6 and the insoluble substances removed by filtration. The filtrate which is a substantially clear liquid is next admixed with corn syrup of about 30 to 35 Baum which has been substantially completely refined and free of coloring matters. Simultaneously with or. sullequent to this mixing, diastase 8 is-nddediand --the.ingredients thoroughly mixed.

The ingredients are'mixeddn proportions erably to give the mixture about 50 mayrange however between about 35% and 55% solids, preferably as high as practical to -spray. Normally this involvesproportions or about'rl tofl partsof-the corn" syrup liquor to one-half-to-two no parts of'fthe reflnedsteeprwater; the variations inipropor tions depending .upon the desiredprotein and salt content in .the'ilnish'ed unso nd 1 uct. 1

In preparing-the above refined steep. water. corn syrup and diastase' no heating for" concentration is used but only that required to effect thorough mixing. Likewise, in the preparation of the steep water the temperat ire is raised only to that required for the specified concentration. More specifically, the heating is minimiz d to prevent reaction of the proteins, salts and carbohydrates which would cause strong flavor formation, discoloration and destruction of the diastase.

reaction may be brought about either before the 76 For producing the desired dried, comminuted tioned above, in the final product. The spraydried material is dehydrated down to a moisture content of about 3% or less. It is in the form of small, generally spherical or rounded discrete particles which are free flowing and satisfactorily stable against hygroscopic tendencies. This product is substantially colorless and has a very slight cereal-like flavor. This is in contrast to the malt-like flavored and dark products that would be produced by the high temperaturetreatments discussed above.

A typical example of the product resulting from spray drying a mixture of the kind described above has the following composition:

Per cent The diastatic activity of the spray dried products or this invention may be varied from about 20 to 150 Lintner value by varying the amount and kind of diastase used. When using malt extract as the diastase material the diastatic activity of the finished product will range generally between about 20 to 40 Lintner value, and when using the diastase concentrate the diastatic activity will range generally from about 40 to 150 Lintner value. The term Lintner value, as used herein to express diastatic activity, is-deflned in and is determined by the method described in the American Handy Book of the Brewing, Maltfiour, starch, and partially gelatinized starch and protein materials.

The spray-dried products of this invention are particularly characterized by their high assimilability, nutritive character, desirable taste and freedom from undesirable color. They contain a high. concentration of the desirable soluble proteins, salts, sugars and carbohydrates and are markedly free of the objectionable insoluble proteins and heat coagulable substances. Th soluble proteins supply adequate amounts of assimilable nitrogen to maintain maximum micro-organism action when the composition is used as ing and Auxiliary Trades, third edition volume I. 7

a bread conditioner. The phosphates catalyze the micro-organism action by combining with the hexose sugars and make them more labile for the micro-organism action; while the mineral salts stimulate the organisms without forming any chemical combinations with reacting substances. The reducing sugars are utilized particularly in fermentation, and the diastase acts to convert the starch, in a bakery product for example, to render it assimilable in fermentation.

What is claimed is:

1. A method of making a substantially dry, non-hygroscopic, free-flowing nutritive composition comprising a coacted product of a starch conversion syrup having a reducing sugars content of between about 25% and calculated as dextrose and soluble proteins, which method comprises intimately mixing such a starch conversion wrup with a separately concentrated solution of soluble, substantially non-coagulable proteins of corn steep water, adjusting the pH to about 4.5 to 6.5, heating the mixture to a tem perature ranging from about up to less than F. to condition the mixture for spray-drying but without developing any dark color therein and without eflecting substantial further concentration, and when spray-drying the mixture at a temperature not in excess of 150 F. to a moisture content not substantially above 3%.

2. A process as specified in claim 1 in which the material is not heated to a temperature substantially in excess of 125 F.-until dried.

3. A method as specified in claim 1 in which the materials treated are corn syrup and the noncoagulable corn steep water proteins.

JAMES F. WALSH. 

